Electronics Timeline - Greatest Engineering Achievements of the Twentieth Century Electronics Timeline Brilliant inventors from the late 19th century to the present day have built on each other's work to launch a revolution in electronics. In recognizing the team of Bardeen, Brattain, and Shockley for their invention of the transistor, the Nobel Prize also paid tribute to their predecessors, the discoverers of electrons, the vacuum tube, purified crystals, and diodes. The transistor spurred experimentation with new materials such as silicon and with a host of manufacturing techniques, leading to electronic devices that have altered every aspect of daily life. Thermionic valve, or diode invented Sir John Ambrose Fleming, a professor of electrical engineering and the first scientific adviser for the Marconi Company, invents the thermionic valve, or diode, a two-electrode rectifier. (A rectifier prevents the flow of current from reversing.) Building on the work of Thomas Edison, Fleming devises an "oscillation valve"—a filament and a small metal plate in a vacuum bulb. He discovers that an electric current passing through the vacuum is always unidirectional.

1907 Triode patented Lee De Forest, an American inventor, files for a patent on a triode, a three-electrode device he calls an Audion. He improves on Fleming’s diode by inserting a gridlike wire between the two elements in the vacuum tube, creating a sensitive receiver and amplifier of radio wave signals. The triode is used to improve sound in long-distance phone service, radios, televisions, sound on film, and eventually in modern applications such as computers and satellite transmitters. 1940 Ohl discovers that impurities in semiconductor crystals create photoelectric properties Russell Ohl, a researcher at Bell Labs, discovers that small amounts of impurities in semiconductor crystals create photoelectric and other potentially useful properties. When he shines a light on a silicon crystal with a crack running through it, a voltmeter attached to the crystal registers a half-volt jump. The crack, it turns out, is a natural P-N junction, with impurities on one side that create an excess of negative electrons (N) and impurities on the other side that create a deficit (P). Ohl’s crystal is the precursor of modern-day solar cells, which convert sunlight into electricity. It also heralds the coming of transistors.

1947 First pointcontact transistor John Bardeen, Walter H. Brattain, and William B. Shockley of Bell Labs discover the transistor. Brattain and Bardeen build the first pointcontact transistor, made of two gold foil contacts sitting on a germanium crystal. When electric current is applied to one contact, the germanium boosts the strength of the current flowing through the other contact. Shockley improves on the idea by building the junction transistor—"sandwiches" of N- and P-type germanium. A weak voltage applied to the middle layer modifies a current traveling across the entire "sandwich." In November 1956 the three men are awarded the Nobel Prize in physics. 1952 First commercial device to apply Shockley’s junction transistor Sonotone markets a $229.50 hearing aid that uses two vacuum tubes and one transistor—the first commercial device to apply Shockley’s junction transistor. Replacement batteries for transistorized hearing aids cost only $10, not the nearly $100 of batteries for earlier vacuum tube models.

1954 First truly consistent mass-produced transistor is demonstrated Gordon Teal, a physical chemist formerly with Bell Labs, shows colleagues at Texas Instruments that transistors can be made from pure silicon—demonstrating the first truly consistent mass-produced transistor. By the late 1950s silicon begins to replace germanium as the semiconductor material out of which almost all modern transistors are made. 1954 First transistor radio Texas Instruments introduces the first transistor radio, the Regency TR1, with radios by Regency Electronics and transistors by Texas Instruments. The transistor replaces De Forest’s triode, which was the electrical component that amplified audio signals—making AM (amplitude modulation) radio possible. The door is now open to the transistorization of other mass production devices. 1955 Silicon dioxide discovery Carl Frosch and Link Derick at Bell Labs discover that silicon dioxide can act as a diffusion mask. That is, when a silicon wafer is heated to about 1200°C in an atmosphere of water vapor or oxygen, a thin skin of silicon dioxide forms on the surface. With selective etching of the oxide layer, they could diffuse impurities into the silicon to create P-N junctions.

Bell Labs engineer John Moll then develops the all-diffused silicon transistor, in which impurities are diffused into the wafer while the active elements are protected by the oxide layer. Silicon begins to replace germanium as the preferred semiconductor for electronics. 1958-1959 Integrated circuit invented Jack Kilby, an electrical engineer at Texas Instruments and Robert Noyce of Fairchild Semiconductor independently invent the integrated circuit. In September 1958, Kilby builds an integrated circuit that includes multiple components connected with gold wires on a tiny silicon chip, creating a "solid circuit." (On February 6, 1959, a patent is issued to TI for "miniaturized electronic circuits.") In January 1959, Noyce develops his integrated circuit using the process of planar technology, developed by a colleague, Jean Hoerni. Instead of connecting individual circuits with gold wires, Noyce uses vapor-deposited metal connections, a method that allows for miniaturization and mass production. Noyce files a detailed patent on July 30, 1959.

1962 MOSFET is invented The metal oxide semiconductor field effect transistor (MOSFET) is invented by engineers Steven Hofstein and Frederic Heiman at RCA's research laboratory in Princeton, New Jersey. Although slower than a bipolar junction transistor, a MOSFET is smaller and cheaper and uses less power, allowing greater numbers of transistors to be crammed together before a heat problem arises. Most microprocessors are made up of MOSFETs, which are also widely used in switching applications. 1965 Automatic adaptive equalizer invented by Robert Lucky The automatic adaptive equalizer is invented in 1965 at Bell Laboratories by electrical engineer Robert Lucky. Automatic equalizers correct distorted signals, greatly improving data performance and speed. All modems still use equalizers. 1966 Self-aligned gate process for fabricating field effect transistors In 1966 Dr. Robert W. Bower invents the self-aligned gate process for fabricating field effect transistors, providing the foundation for later developments establishing the core technology for the fabrication of high performance MOS integrated circuits.

1967 First handheld calculator invented A Texas Instruments team, led by Jack Kilby, invents the first handheld calculator in order to showcase the integrated circuit. Housed in a case made from a solid piece of aluminum, the battery-powered device fits in the palm of a hand and weighs 45 ounces. It accepts six-digit numbers and performs addition, subtraction, multiplication, and division, printing results up to 12 digits on a thermal printer. 1968 Bell Labs team develops molecular beam epitaxy Alfred Y. Cho heads a Bell Labs team that develops molecular beam epitaxy, a process that deposits single-crystal structures one atomic layer at a time, creating materials that cannot be duplicated by any other known technique. This ultra-precise method of growing crystals is now used worldwide for making semiconductor lasers used in compact disc players. (The term epitaxy is derived from the Greek words epi, meaning "on" and taxis, meaning "arrangement.") 1969 Dynamic random access memory In 1969 Dr. Robert H. Dennard invents the 1-transistor dynamic random access memory (DRAM), providing a large increase in memory density and speed.

Dennard’s design remains today as the critical memory component in all computers. 1970 The first CD-ROM patented James T. Russell, working at Battelle Memorial Institute's Pacific Northwest Laboratories in Richland, Washington, patents the first systems capable of digital-to-optical recording and playback. The CD-ROM (compact disc read-only memory) is years ahead of its time, but in the mid-1980s audio companies purchase licenses to the technology. (See computers.) Russell goes on to earn dozens of patents for CD-ROM technology and other optical storage systems. 1971 Intel introduces "computer on a chip" Intel, founded in 1968 by Robert Noyce and Gordon Moore, introduces a "Computer on a chip," the 4004 four-bit microprocessor, design by Frederico Faggin, Ted Hoff, and Stan Mazor. It can execute 60,000 operations per second and changes the face of modern electronics by making it possible to include data processing hundreds of devices. A 4004 provides the computing power for NASA's Pioneer 10 spacecraft, launched the following year to survey Jupiter.

3M Corporation introduces the ceramic chip carrier, designed to protect integrated circuits when they are attached or removed from circuit boards. The chip is bonded to a gold base inside a cavity in the square ceramic carrier, and the package is then hermetically sealed. 1972 Home video game systems become available In September, Magnavox ships Odyssey 100 home game systems to distributors. The system is test marketed in 25 cities, and 9,000 units are sold in Southern California Alone during the first month at a price of $99.95. In November, Nolan Bushnell forms Atari and ships Pong, a coin-operated video arcade game, designed and built by Al Alcorn. The following year Atari introduces its home version of the game, which soon outstrips Odyssey 100. 1974 Texas Instruments introduces the TMS 1000 Texas Instruments introduces the TMS 1000, destined to become the most widely used computer on a chip. Over the next quarter-century, more than 35 different versions of the chip are produced for use in toys and games, calculators, photcopying machines, appliances, burglar alarms, and jukeboxes.

(Although TI engineers Michael Cochran and Gary Boone create the first microcomputer, a four-bit microprocessor, at about the same time Intel does in 1971, TI does not put its chip on the market immediately, using it in a calculator introduced in 1972.) 1980 First circuit boards that have built-in self-testing technology Chuck Stroud, while working at Bell Laboratories, develops and designs 21 different microchips and three different circuit boards—the first to employ built-in self-testing (BIST) technology. BIST results in a significant reduction in the cost, and a significant increase in the quality of producing electronic components. 1997 IBM develops a copper-based chip technology IBM announces that it has developed a copper-based chip technology, using copper wires rather than traditional aluminum to connect transistors in chips. Other chip manufacturers are not far behind, as research into copper wires has been going on for about a decade. Copper, the better conductor, offers faster performance, requires less electricity, and runs at lower temperatures, This breakthrough allows up to 200 million transistors to be placed on a single chip.

1998 Plastic transistors developed A team of Bell Labs researchers—Howard Katz, V. Reddy Raju, Ananth Dodabalapur, Andrew Lovinger, and chemist John Rogers—present their latest findings on the first fully "printed" plastic transistor, which uses a process similar to silk screening. Potential uses for plastic transistors include flexible computer screens and "smart" cards, full of vital statistics and buying power, and virtually indestructible. De Forest - definition of De Forest by The Free Dictionary De Forest - definition of De Forest by The Free Dictionary Also found in: Thesaurus , Encyclopedia , Wikipedia . De For·est (dĭ fôr′ĭst, fŏr′-), Lee 1873-1961. American electrical engineer who patented the triode electron tube (1907) that made possible the amplification and detection of radio waves. He originated radio news broadcasts in 1916. De Forest (də ˈfɒrɪst) n (Biography) Lee.

1873–1961, US inventor of telegraphic, telephonic, and radio equipment: patented the first triode valve (1907) De For•est Lee, 1873–1961, U.S. inventor. de•for•est to divest or clear of forests or trees. [1530–40] de•for`est•a′tion, n. de•for′est•er, n. ThesaurusAntonymsRelated WordsSynonymsLegend: Noun 1. De Forest - United States electrical engineer who in 1907 patented the first triode vacuum tube, which made it possible to detect and amplify radio waves (1873-1961) Want to thank TFD for its existence? Tell a friend about us , add a link to this page, or visit the webmaster's page for free fun content . Link to this page: Lee De Forest References in periodicals archive ?

24, 2015 /PRNewswire-USNewswire/ -- Park West Gallery, known for fine art auctions on cruise ships, live art auctions in major metropolitan areas and art galleries in Detroit and Miami Lakes, Florida, is pleased to announce that one of its artists, Autumn de Forest, has been named the recipient of the International Vatican Award in Painting and Art. Radio & Television Timeline - Greatest Engineering Achievements of the Twentieth Century Radio & Television Timeline Radio and television were major agents of social change in the 20th century, opening windows to other peoples and places and bringing distant events directly into millions of homes. Although Guglielmo Marconi was the first to put the theory of radio waves into practice, the groundwork for his feat was laid in the 19th century by James Clerk Maxwell, Heinrich Hertz, and Nikola Tesla. Maxwell theorized and Hertz confirmed the feasibility of transmitting electromagnetic signals. Tesla invented a device—the Tesla coil-that converts relatively low-voltage current to high—voltage low current at high frequencies. Some form of the coil is still used in radio and television sets today. Tesla granted a U.S. patent Nikola Tesla is granted a U.S.

patent for a "system of transmitting electrical energy" and another patent for "an electrical transmitter"—both the products of his years of development in transmitting and receiving radio signals. These patents would be challenged and upheld (1903), reversed (1904), and finally restored (1943). 1901 Marconi picks up the first transatlantic radio signal Guglielmo Marconi, waiting at a wireless receiver in St. John’s, Newfoundland, picks up the first transatlantic radio signal, transmitted some 2,000 miles from a Marconi station in Cornwall, England. To send the signal—the three dots of the Morse letter "s"—Marconi’s engineers send a copper wire aerial skyward by hoisting it with a kite. Marconi builds a booming business using radio as a new way to send Morse code. 1904 Fleming invents the vacuum diode British engineer Sir John Ambrose Fleming invents the two-electrode radio rectifier; or vacuum diode, which he calls an oscillation valve. Based on Edison's lightbulbs, the valve reliably detects radio waves.

Transcontinental telephone service becomes possible with Lee De Forest's 1907 patent of the triode, or three-element vacuum tube, which electronically amplifies signals. 1906 Audion Expanding on Fleming’s invention, American entrepreneur Lee De Forest puts a third wire, or grid, into a vacuum tube, creating a sensitive receiver. He calls his invention the "Audion." In later experiments he feeds the Audion output back into its grid and finds that this regenerative circuit can transmit signals. 1906 Christmas Eve 1906 program On Christmas Eve 1906 engineering professor Reginald Fessenden transmits a voice and music program in Massachusetts that is picked up as far away as Virginia. 1912 Radio signal amplifier devised Columbia University electrical engineering student Edwin Howard Armstrong devises a regenerative circuit for the triode that amplifies radio signals. By pushing the current to the highest level of amplification, he also discovers the key to continuous-wave transmission, which becomes the basis for amplitude modulation (AM) radio.

In a long patent suit with Lee De Forest, whose three-element Audion was the basis for Armstrong’s work, the courts eventually decide in favor of De Forest, but the scientific community credits Armstrong as the inventor of the regenerative circuit. 1917 Superheterodyne circuit While serving in the U.S. Army Signal Corps during World War I, Edwin Howard Armstrong invents the superheterodyne circuit, an eight-tube receiver that dramatically improves the reception of radio signals by reducing static and increasing selectivity and amplification. He files for a patent the following year. 1920 First scheduled commercial radio programmer Station KDKA in Pittsburgh becomes radio’s first scheduled commercial programmer with its broadcast of the Harding-Cox presidential election returns, transmitted at 100 watts from a wooden shack atop the Westinghouse Company’s East Pittsburgh plant.

Throughout the broadcast KDKA intersperses the election returns and occasional music with a message: "Will anyone hearing this broadcast please communicate with us, as we are anxious to know how far the broadcast is reaching and how it is being received?" 1925 Televisor Scottish inventor John Logie Baird successfully transmits the first recognizable image—the head of a ventriloquist’s dummy—at a London department store, using a device he calls a Televisor. A mechanical system based on the spinning disk scanner developed in the 1880s by German scientist Paul Nipkow, it requires synchronization of the transmitter and receiver disks. The Televisor images, composed of 30 lines flashing 10 times per second, are so hard to watch they give viewers a headache. Charles F. Jenkins pioneers his mechanical wireless television system, radiovision, with a public transmission sent from a navy radio station across the Anacostia River to his office in downtown Washington, D.C. Jenkins’s radiovisor is a multitube radio set with a special scanning-drum attachment for receiving pictures—cloudy 40- to 48-line images projected on a six-inch-square mirror.

Jenkins’s system, like Baird’s, broadcasts and receives sound and visual images separately. Three years later the Federal Radio Commission grants Charles Jenkins Laboratories the first license for an experimental television station. 1927 All-electronic television system Using his all-electronic television system, 21-year-old Utah farm boy and electronic prodigy Philo T. Farnsworth transmits images of a piece of glass painted black, with a center line scratched into the paint. The glass is positioned between a blindingly bright carbon arc lamp and Farnsworth’s "image dissector" cathode-ray camera tube. As viewers in the next room watch a cathode-ray tube receiver, someone turns the glass slide 90 degrees—and the line moves. The use of cathode-ray tubes to transmit and receive pictures—a concept first promoted by British lighting engineer A. Campbell Swinton—is the death knell for the mechanical rotating-disk scanner system. 1928 Televisor system produces images in crude color John Logie Baird demonstrates, with the aid of two ventriloquist’s dummies, that his Televisor system can produce images in crude color by covering three sets of holes in his mechanical scanning disks with gels of the three primary colors.

The results, as reported in 1929 following an experimental BBC broadcast, appear "as a soft-tone photograph illuminated by a reddish-orange light." 1929 Television camera and a cathode-ray tube receiver Vladimir Zworykin, who came to the United States from Russia in 1919, demonstrates the newest version of his iconoscope, a cathode-ray-based television camera that scans images electronically, and a cathode-ray tube receiver called the kinescope. The iconoscope, first developed in 1923, is similar to Philo Farnsworth’s "image dissector" camera tube invention, fueling the growing rivalry between the two inventors for the eventual title of "father of modern television." 1933 FM radio Edwin Howard Armstrong develops frequency modulation, or FM, radio as a solution to the static interference problem that plagues AM radio transmission, especially in summer when electrical storms are prevalent. Rather than increasing the strength or amplitude of his radio waves, Armstrong changes only the frequency on which they are transmitted. However, it will be several years before FM receivers come on the market.

1947 Transistor is invented The future of radio and television is forever changed when John Bardeen, Walter Brattain, and William Shockley of Bell Laboratories co-invent the transistor. 1950s Cathode-ray tube (CRT) for television monitors improved Engineers improve the rectangular cathode-ray tube (CRT) for television monitors, eliminating the need for rectangular "masks" over the round picture tubes of earlier monitors. The average price of a television set drops from $500 to $200. 1953 RCA’s new system for commercial color adopted RCA beats out rival CBS when the National Television System Committee adopts RCA’s new system for commercial color TV broadcasting. CBS has pioneered color telecasting, but its system is incompatible with existing black-and-white TV monitors throughout the country. 1954 First coast-to-coast color television transmission The New Year’s Day Tournament of Roses in Pasadena, California, becomes the first coast-to-coast color television transmission, or "colorcast." The parade is broadcast by RCA’s NBC network to 21 specially equipped stations and is viewed on newly designed 12-inch RCA Victor receivers set up in selected public venues.

Six weeks later NBC’s Camel News Caravan transmits in color, and the following summer the network launches its first color sitcom, The Marriage, starring Hume Cronyn and Jessica Tandy. 1954 First all-transistor radio Regency Electronics introduces the TR-1, the first all-transistor radio. It operates on a 22-volt battery and works as soon as it is switched on, unlike tube radios, which take several minutes to warm up. The TR-1 sells for $49.95; is available in six colors, including mandarin red, cloud gray and olive green; and is no larger than a package of cigarettes. 1958 Integrated circuit Jack S. Kilby of Texas Instruments and Robert Noyce of Fairchild Semiconductor, working independently, create the integrated circuit, a composite semiconductor block in which transistor, resistor, condenser, and other electrical components are manufactured together as one unit. Initially, the revolutionary invention is seen primarily as an advancement for radio and television, which together were then the nation’s largest electronics industry.

1962 Telstar 1 Communications satellite Telstar 1 is launched by a NASA Delta rocket on July 10, transmitting the first live transatlantic telecast as well as telephone and data signals. At a cost of $6 million provided by AT&T, Bell Telephone Laboratories designs and builds Telstar, a faceted sphere 34 inches in diameter and weighing 171 pounds. The first international television broadcasts shows images of the American flag flying over Andover, Maine to the sound of "The Star-Spangled Banner." Later that day AT&T chairman Fred Kappel makes the first long-distance telephone call via satellite to Vice President Lyndon Johnson. Telstar I remains in orbit for seven months, relaying live baseball games, images from the Seattle World's Fair, and a presidential news conference. 1968 200 million television sets There are 200 million television sets in operation worldwide, up from 100 million in 1960. By 1979 the number reaches 300 million and by 1996 over a billion.

In the United States the number grows from 1 million in 1948 to 78 million in 1968. In 1950 only 9 percent of American homes have a TV set; in 1962, 90 percent; and in 1978, 98 percent, with 78 percent owning a color TV. 1988 Sony "Watchman" Sony introduces the first in its "Watchman" series of handheld, battery-operated, transistorized television sets. Model FD-210, with its 1.75-inch screen, is the latest entry in a 30-year competition among manufacturers to produce tiny micro-televisions. The first transistorized TV, Philco’s 1959 Safari, stood 15 inches high and weighed 15 pounds. 1990 FCC sets a testing schedule for proposed all-digital HDTV system Following a demonstration by Philips two years earlier of a high-definition TV (HDTV) system for satellite transmission, the Federal Communications Commission sets a testing schedule for a proposed all-digital HDTV system.

Tests begin the next year, and in 1996 Zenith introduces the first HDTV-compatible front-projection television. Also in 1996, broadcasters, TV manufacturers, and PC makers set inter-industry standards for digital HDTV. By the end of the century, digital HDTV, which produces better picture and sound than analog television and can transmit more data faster, is on the verge of offering completely interactive TV. Diode - Engineering and Technology History Wiki Request account Diode John Fleming's valve or diode (1904) allowed electrical current to flow in one direction only. Courtesy: Science Museum/Science & Society Picture Library. Fleming Diode The diode is one of the oldest and most important electronic devices, although it is not as famous as its cousin, the transistor. Used in all sorts of electrical and electronic systems, the diode functions as a one-way valve for electric current—it only allows current to flow in one direction. This is useful in converting AC to DC, processing high frequency signals, regulating voltages, and in other applications. There are two basic types of diodes. One is an electron tube similar to the triode. The other type uses semiconductors , like the transistor.

Both were invented early in the 20th century. The first diode was a modified light bulb. Thomas Edison discovered that including an extra electrode in a light bulb and connecting it to the positive side of a battery resulted in a current flowing from the filament through the empty space. He was not sure what to do with this discovery, and moved on to other projects. Joseph J. Thomson (1856~1940) announced the discovery of the electron in April 1897 and explained the Edison effect where current travels just one way through a vacuum tube. Thompson received a Nobel prize in 1906. Others found another use for this device. In the early 1900s, for example, English engineer John Ambrose Fleming used this one-way electrical “valve,” to convert radio waves into a flow of current that could be measured by a galvanometer. The Fleming valve is remembered as the first true electronic device. It came into use for radio transmission and soon became the basis of Lee De Forest’s Audion electron tube, which he invented in 1906. Also around 1906, American engineer Greenleaf W.

Pickard invented a new type of diode. Pickard based his design on the earlier discovery that electricity can flow in only one direction through certain types of mineral crystals, such as silicon. By placing a silicon crystal between a metal base and a carefully placed fine wire, Pickard created a valve that could also be used to detect radio waves. This type of “cat’s whisker” diode (so-named because of the fine wire used in it) became more popular after American H. C. Dunwoody patented a version of it that used a material called carborundum. Part of a 1920s cat’s whisker diode that uses a small crystal of the semiconductor galena. A fine piece of wire—the “cat’s whisker”—is touched on the surface until the “sweet spot” is located. The crystal then acts as a one-way valve for electrical current and can be used to separate a radio signal from its carrier wave. Courtesy: Lorne Clark. In the early 1900s, cat’s whisker diodes were widely used in radio receivers, as they were an improvement over electron tubes. But they too had limitations. They required careful adjustment and could easily be knocked out of alignment.

For these reasons the use of cat’s whisker diodes declined, although their ability to work at very high frequencies made them valuable during World War II when they were used in radar receivers. During the war years, thousands were manufactured, and in the course of research on semiconductors, Bell Laboratories scientists stumbled on a new type of diode. Russell Ohl, a Bell Labs metallurgist working with silicon samples discovered that one of his samples acted like a diode and—even more remarkable—produced electricity in response to light. He had invented a new type of diode that was also an efficient solar energy converter or “cell.” The reason it worked either as a diode or as a solar cell was a mystery to the researchers. Eventually, however, they determined that the sample, which had been cut from a larger piece of silicon, had a region that contained high levels of a certain kind of impurity. The area where this region joined the rest of the silicon formed a “junction.” This junction had something to do with the diode action of the device. The junction and the different regions of impurity also allowed it to respond to light.

It would be many years before physicists explained why this worked, but in the meantime, semiconductor junction diodes went into production, first as solar cells and eventually as ordinary diodes. Today the variety of diodes and their uses have greatly expanded. Electron-tube diodes are rarely used, but silicon diodes are used in many types of equipment to detect high frequency electromagnetic waves, to convert sunlight into electricity, and many other purposes. Inside computers, televisions, and other familiar systems are diodes that help convert alternating current (AC) electricity to direct current (DC), and to regulate the level of the voltage. High-power diodes are used in automobiles, where they convert the AC from the alternator into DC that the battery and on-board electronics can use. Light emitting diodes (LEDs), perfected in the early 1960s, have replaced incandescent lamps for many purposes, and may soon replace the lamps used in car headlights and household light bulbs. Historical Diodes (Rectifiers) Here is a partial list of the type of diodes invented, constructed and used over time, many comprise of hazardous materials: Chemical Rectifier, known as the Nodon Valve using lead and aluminium electrodes.

Copper type rectifier (used lead and copper junctions, also copper sulphide and magnesium junctions) Selenium Rectifier Electrolytic Rectifier Gaseous Rectifier, Argon arc rectifier Mechanical Rectifier, colloquially known as the vibrator, obsoleted from industrial applications around 1921, but used in vacuum tube mobile radio equipment up until 1958. Also a rotational synchronous rectifier Mercury Arc Rectifier, also Mercury Vapour Rectifier Photo diode tube, also photomultiplier, gamma ray detector More recent solid state diodes: Silicon Diode, Photodiode, Silicon Controlled rectifier (SCR) Metal-Oxide-Metal Diode, invented around 1975, and a variant of the Schotty diode, see text authors V A Ivanov, A A Rivlin and V S Solov'ev and Izmeritelnaya Tekhnika, No. 11, p. 33, November, 1980. Used for detection and mixers into the near-infra-red wavelengths.

S Tube Rectifier The S Tube Rectifier.-The S tube rectifier has been developed by the American Radio and Research Corporation, and is often used by American amateurs instead of the usual form of two-electrode valve rectifier. The anode is a flat carbon electrode, and the cathode is cup-shaped, with a small tube-like opening, as illustrated. The tube contains helium at about 12 mm. pressure. When the anode is made positive, free electrons are drawn from all parts of the cup through the opening to the anode. S Tube Rectifier circa 1922 In doing so they collide with the atoms of the helium and ionise them. The action is cumulative, and hence the tube conducts. When the cup is made positive the action is very different. Positive ions in the cup, being much larger in bulk, are less mobile, and but comparatively few of them reach the cathode (cup). The movement of the positive ions is so sluggish, and the number which reach the cathode so few, that the current conduction is less than 1 per cent. of the normal current carrying capacity when the polarity is reversed. S tubes are manufactured for supplying D.C.

anode potentials to 5-watt 1 transmitting valves. They are rated at 20 watts each, the normal current being 50 milliamperes. The tube has a practically constant drop of 150 volts, and will stand 2,000 volts in the reverse direction. Two rectifier tubes will supply sufficient current for one 50-watt 1 transmitting valve. Other old diodes were: The Free Information Society - De Forest, Lee Articles / Biographies / Other /De Forest, Lee Lee De Forest was born on August 26, 1873 in Iowa. His father was a minister and dreamed that his son would one day follow in his footsteps. The family moved to Alabama after his father was appointed president of Talladega College, a primarily black school. After graduating from Mount Hermon School, De Forest applied at Yale University and was accepted in 1893. He studied electrical engineering and started to work on inventing things. While experimenting one day, he accidentally shorted the school's electrical system and blacked out the entire campus.

As a result he was suspended for some time, but eventually he was able to graduate with a Bachelor's degree in 1896. After graduation, he continued studying at Yale, receiving a Ph.D. in electrical engineering in 1899. His dissertation focused on radio waves, one of the hot topics in science at the time. In 1906, he invented the "Audion Tube", a dual electrode vacuum tube that was specifically designed to amplify radio signals. De Forest was a charter member of the Institute of Radio Engineers, a group of engineers and scientists that were interested in radio transmission and reception. The group later evolved into IEEE, the modern organization of electrical and electronic engineers. In 1907, he developed a version of his Audion tube with three electrodes instead of two. The tube became known as the De Forest valve, more popularly known as the triode. The triode was essentially a diode with a metal grid between the filament and plate. The new configuration made it possible to use the triode for amplification and switching (much like modern transistors).

In 1916, De Forest filed a patent for a regenerative circuit, but had to fight another inventor, Edwin Armstrong, who had already received a patent for the idea in 1914. The lawsuit extended for twelve years, eventually reaching the United States Supreme Court. The final ruling was in favor of De Forest having the rights to the patent of the regenerative circuit. That same year, he also broadcasted the first radio advertisement and presidential election report via his own radio station. He continued to broadcast radio shows, but found that he was unable to get the necessary financial backing. In 1922, De Forest developed the Phonofilm process. The process was a new method of recording sound for movies, accomplished by recording sound directly onto the film in the form of two parallel lines. Although Hollywood initially ignored his invention, it later became the standard in movie production and he was credited with the invention of sound recording for motion pictures. In 1931, he sold a radio manufacturing firm that he had owned to RCA. In 1946, De Forest was awarded the Edison Medal of the American Institute of Electrical Engineers for the invention of the triode.

In 1959, he received an Academy Award for "pioneering inventions which brought sound to the motion picture" and was also given a star on the Hollywood Walk of Fame. Lee De Forest died on June 30, 1961 in Hollywood and was buried in Los Angeles. Electronics engineering | Engineering | Fandom powered by Wikia Edit It could be said that the modern discipline of electronics engineering was to a large extent born out of radio and television development and from the large amount of wartime development of defence systems and weapons. In the interwar years, the subject was known as radio engineering and it was only in the late 1950s that the term electronics engineering started to emerge. In the UK, the subject of electronics engineering became distinct from electrical engineering as a university degree subject around 1960. Students of electronics and related subjects like radio and telecomms before this time had to enrol in the electrical engineering department of the university as no university had departments of electronics. Electrical engineering was the nearest subject with which electronics engineering could be aligned, although the similarities in subjects covered (except mathematics and electromagnetism) lasted only for the first year of the three-year course.

The name electrical engineering is still used to cover MANY electronics engineering amongst some of the older (notably American) universities and electronics engineering graduates there are sometimes called electrical engineers . In Europe, graduates of electronics engineering are known properly as electronics engineers, and the term electrical engineer is reserved for those having specialised in power and heavy current or high voltage engingeering. Early radio Edit In 1893, Nikola Tesla made the first public demonstration of radio communication. Addressing the Franklin Institute in Philadelphia and the National Electric Light Association, he described and demonstrated in detail the principles of radio communication. In 1896, Guglielmo Marconi made a wireless radio transmission and went on to develop a practical and widely used radio system. In 1905, John Fleming invented the first radio tube , the diode . One year later, in 1906, Robert von Lieben and Lee De Forest independently developed the amplifier tube, called the triode . In the interwar years the subject of electronics was dominated by the worldwide interest in radio and to some extent telephone and telegraph communications. The terms 'wireless' and 'radio' were then used to refer anything electronic.

There were indeed few non-military applications of electronics beyond radio at that time until the advent of television. The subject was not even offered as a separate university degree subject until about 1960. Edit The invention of the triode amplifier, generator, and detector enabled audio radio. On Christmas Eve, 1906, Reginald Fessenden (using his heterodyne principle) transmitted the first radio audio broadcast in history from Brant Rock, Massachusetts. Ships at sea heard a broadcast that included Fessenden playing O Holy Night on the violin and reading a passage from the Bible. The first known radio news program was broadcast 31 August 1920 by station 8MK, the unlicensed predecessor of WWJ (AM) in Detroit, Michigan. Regular wireless broadcasts for entertainment commenced in 1922 from the Marconi Research Centre at Writtle near Chelmsford, England. While some early radios used some type of amplification through electric current or battery, through the mid 1920s the most common type of receiver was the crystal set. In the 1920s, amplifying vacuum tubes revolutionized both radio receivers and transmitters.

Phonographs and radiograms This is the early name for record players or combined radios and record players that had some prescence in the inter war years. Television Edit In 1931 Manfred von Ardenne introduced the cathode ray tube and thus the electronic television. In the same year, the first successful transatlantic television transmission was made from London to New York. The broadcast television system adopted by the BBC in the UK was the EMI system which was chosen over the inferior mechanical system of John Logie Baird. Radar and radio location Edit During WW2 many efforts were expended in the electronic location of enemy targets and aircraft. These included radio beam guidance of bombers, electronic counter measures, early radar systems etc. During this time very little if any effort was expended on consumer electronics developments. Computers Edit In 1942, Konrad Zuse presented the Z3, the world's first functional computer . In 1946, the ENIAC (Electronic Numerical Integrator and Computer) of John Presper Eckert and John Mauchly followed, beginning the computing era. The arithmetic performance of these machines allowed engineers to develop completely new technologies and achieve new objectives.

Early examples include the Apollo missions and the NASA moon landing. Transistors The invention of the transistor in 1947 by William B. Shockley , John Bardeen and Walter Brattain opened the door for more compact devices and led to the development of the integrated circuit in 1959 by Jack Kilby . Microprocessors Edit In 1968, Marcian Hoff invented the microprocessor at Intel and thus ignited the development of the personal computer. Hoff's invention was part of an order by a Japanese company for a desktop computer, which Hoff wanted to build as cheaply as possible. The first realization of the microprocessor was the Intel 4004, a 4-bit processor, in 1969, but only in 1973 did the Intel 8080, an 8-bit processor, make the building of the first personal computer, the Altair 8800, possible.

Electronics File:Pentium-mmx1.jpg In the subfield of electronics engineering, engineers design and test electrical networks (more commonly known as circuits ) that use the electromagnetic properties of electrical components such as resistors , capacitors , inductors , diodes and transistors to achieve a particular functionality. The tuner circuit , which allows the user of a radio to filter out all but a single station, is just one example of such a circuit. Electronics is often considered to have begun when Lee De Forest invented the vacuum tube in 1907 . Within 10 years, his device was used by radio transmitters and receivers as well as systems for long distance telephone calls . Vacuum tubes remained the preferred amplifying device for 40 years, until researchers working for William Shockley at Bell Labs invented the transistor in 1947 . In the following years, transistors made small portable radios , or transistor radios , possible as well as allowing more powerful mainframe computers to be built. Transistors were cooler, smaller and required lower voltages than vacuum tubes to work. Before the invention of the integrated circuit in 1959 , electronic circuits were constructed from discrete components that could be manipulated by hand.

These non-integrated circuits consumed much space and power , were prone to failure and were limited in speed although they are still common in simple applications. By contrast, integrated circuits packed a large number - often millions - of tiny electrical components, mainly transistors , into a small chip around the size of a coin . This allowed for the powerful computers and other electrical devices we see today. In designing an integrated circuit, electronics engineers first construct circuit schematics that specify the electrical components and describe the interconnections between them. When completed, VLSI engineers convert the schematics into actual layouts, which map the layers of various conductor and semiconductor materials needed to construct the circuit. The conversion from schematics to layouts can be done by software (see electronic design automation ) but very often requires human fine-tuning decrease space and power consumption. Once the layout is complete, it can be sent to a fabrication plant for manufacturing. Integrated circuits and other electrical components can then assembled on printed circuit boards to form more complicated circuits. Today, printed circuit boards are found in most electronic devices including televisions , computers and audio players . Typical electronics engineering undergraduate syllabus Edit Apart from electromagnetics and network theory, other items in the syllabus are particular to electronics engineering course.

Electrical engineering courses have other specialisms such as machines , power generation and distribution . Note that the following list does not include the large quantity of mathematics (maybe apart from the final year) included in each year's study. Electromagnetics Edit Elements of vector calculus: divergence and curl; Gauss' and Stokes' theorems, Maxwell's equations: differential and integral forms. Wave equation, Poynting vector. Plane waves: propagation through various media; reflection and refraction; phase and group velocity; skin depth. Transmission lines: characteristic impedance; impedance transformation; Smith chart; impedance matching; pulse excitation. Waveguides: modes in rectangular waveguides; boundary conditions; cut-off frequencies; dispersion relations. Antennas: Dipole antennas; antenna arrays; radiation pattern; reciprocity theorem, antenna gain. Network theory Edit Network graphs: matrices associated with graphs; incidence, fundamental cut set and fundamental circuit matrices. Solution methods: nodal and mesh analysis. Network theorems: superposition, Thevenin and Norton's maximum power transfer, Wye-Delta transformation. Steady state sinusoidal analysis using phasors.

Linear constant coefficient differential equations; time domain analysis of simple RLC circuits, Solution of network equations using Laplace transform: frequency domain analysis of RLC circuits. 2-port network parameters: driving point and transfer functions. State equations for networks. Electronic devices and circuits Edit Electronic Devices: Energy bands in silicon, intrinsic and extrinsic silicon. Carrier transport in silicon: diffusion current, drift current, mobility, resistivity. Generation and recombination of carriers. p-n junction diode, Zener diode, tunnel diode, BJT, JFET, MOS capacitor, MOSFET, LED, p-I-n and avalanche photo diode, LASERs. Device technology: integrated circuits fabrication process, oxidation, diffusion, ion implantation, photolithography, n-tub, p-tub and twin-tub CMOS process. Analog Circuits: Equivalent circuits (large and small-signal) of diodes, BJTs, JFETs, and MOSFETs. Simple diode circuits, clipping, clamping, rectifier. Biasing and bias stability of transistor and FET amplifiers. Amplifiers: single-and multi-stage, differential, operational, feedback and power. Analysis of amplifiers; frequency response of amplifiers.

Simple op-amp circuits. Filters. Sinusoidal oscillators; criterion for oscillation; single-transistor and op-amp configurations. Function generators and wave-shaping circuits. Power supplies. Digital circuits: Boolean algebra, minimization of Boolean functions; logic gates digital IC families (DTL, TTL, ECL, MOS, CMOS). Combinational circuits: arithmetic circuits, code converters, multiplexers and decoders. Sequential circuits: latches and flip-flops, counters and shift-registers. Sample and hold circuits, ADCs, DACs. Semiconductor memories. Microprocessor(8085): architecture, programming, memory and I/O interfacing. Signals and systems Edit Definitions and properties of Laplace transform, continuous-time and discrete-time Fourier series, continuous-time and discrete-time Fourier Transform, z-transform. Sampling theorems. Linear Time-Invariant (LTI) Systems: definitions and properties; casuality, stability, impulse response, convolution, poles and zeros frequency response, group delay, phase delay. Signal transmission through LTI systems. Random signals and noise: probability, random variables, probability density function, autocorrelation, power spectral density.

Control systems Edit Basic control system components; block diagrammatic description, reduction of block diagrams. Open loop and closed loop (feedback) systems and stability analysis of these systems. Signal flow graphs and their use in determining transfer functions of systems; transient and steady state analysis of LTI control systems and frequency response. Tools and techniques for LTI control system analysis: root loci, Routh-Hurwitz criterion, Bode and Nyquist plots. Control system compensators: elements of lead and lag compensation, elements of Proportional-Integral-Derivative (PID) control. State variable representation and solution of state equation of LTI control systems. Communications Edit Analog communication systems: amplitude and angle modulation and demodulation systems, spectral analysis of these operations, superheterodyne receivers; elements of hardware, realizations of analog communication systems; signal-to-noise ratio (SNR) calculations for amplitude modulation (AM) and frequency modulation (FM) for low noise conditions.

Digital communication systems: pulse code modulation (PCM), differential pulse code modulation (DPCM), delta modulation (DM); digital modulation schemes-amplitude, phase and frequency shift keying schemes (ASK, PSK, FSK), matched filter receivers, bandwith consideration and probability of error calculations for these schemes. Education and training Edit Electronics engineers typically possess an academic degree with a major in electronics engineering. The length of study for such a degree is usually three or four years and the completed degree may be designated as a Bachelor of Engineering, Bachelor of Science or Bachelor of Applied Science depending upon the university. The degree generally includes units covering physics , mathematics , project management and specific topics in electrical engineering . Initially such topics cover most, if not all, of the subfields of electronics engineering. Students then choose to specialize in one or more subfields towards the end of the degree. Some electronics engineers also choose to pursue a postgraduate degree such as a Master of Engineering, a Doctor of Philosophy in Engineering or an Engineer's degree. The Master degree is being introduced in some European and American Universities as a first degree and the differentiation of an engineer with graduate and postgraduate studies is often difficult. In these cases, experience is taken into account.

The Master and Engineer's degree may consist of either research, coursework or a mixture of the two. The Doctor of Philosophy consists of a significant research component and is often viewed as the entry point to academia. In most countries, a Bachelor's degree in engineering represents the first step towards certification and the degree program itself is certified by a professional body. After completing a certified degree program the engineer must satisfy a range of requirements (including work experience requirements) before being certified. Once certified the engineer is designated the title of Professional Engineer (in the United States and Canada), Chartered Engineer (in the United Kingdom, Ireland, India, South Africa and Zimbabwe), Chartered Professional Engineer (in Australia) or European Engineer (in much of the European Union). Fundamental to the discipline are the sciences of physics and mathematics as these help to obtain both a qualitative and quantitative description of how such systems will work. Today most engineering work involves the use of computers and it is commonplace to use computer-aided design programs when designing electronic systems. Although most electronic engineers will understand basic circuit theory, the theories employed by engineers generally depend upon the work they do.

For example, quantum mechanics and solid state physics might be relevant to an engineer working on VLSI but are largely irrelevant to engineers working with macroscopic electrical systems. Edit The advantages of certification vary depending upon location. For example, in the United States and Canada "only a licensed engineer may seal engineering work for public and private clients". [2] This requirement is enforced by state and provincial legislation such as Quebec's Engineers Act. [3] In other countries, such as Australia, no such legislation exists. Practically all certifying bodies maintain a code of ethics that they expect all members to abide by or risk expulsion. [4] In this way these organizations play an important role in maintaining ethical standards for the profession. Even in jurisdictions where certification has little or no legal bearing on work, engineers are subject to the law. For example, much engineering work is done by contract and is therefore covered by contract law. In cases where an engineer's work fails he or she may be subject to the tort of negligence and, in extreme cases, the charge of criminal negligence. [5] An engineer's work must also comply with numerous other rules and regulations such as building codes and legislation pertaining to environmental law.

From the global positioning system , electronics engineers are responsible for a wide range of technologies. They design, develop, test and supervise the deployment of systems and electronic devices. For example, they may work on the design of telecommunication systems. Professional bodies Edit Professional bodies of note for electrical engineers include the Institute of Electrical and Electronics Engineers (IEEE) and the Institution of Electrical Engineers ( IEE ). The IEEE claims to produce 30 percent of the world's literature in electrical/electronics engineering, has over 360,000 members worldwide and holds over 300 conferences annually. [6] The IEE publishes 14 journals, has a worldwide membership of 120,000, certifies Chartered Engineers in the United Kingdom and claims to be the largest professional engineering society in Europe. [7] [8] Modern electronics engineering Edit Electronics engineering in Europe is a very broad field that encompasses many subfields including those that deal with, electronic devices and circuit design , control systems , electronics and telecommunications , computer systems , embedded software etc. Many European universities now have departments of Electronics that are completely separate from or have completely replaced their electrical engineering departments.

List of universities with separate Electronics departments Edit Electronics engineering involves the design and testing of electronic circuits that use the electronic properties of components such as resistors , capacitors , inductors , diodes and transistors to achieve a particular functionality. Before the invention of the integrated circuit in 1959 , electronic circuits were constructed from discrete components. These non-integrated circuits consumed much space and power , and were limited in speed although they are still common in simple applications. By contrast, integrated circuits packed a large number - often millions - of tiny electrical components, mainly transistors , into a small chip around the size of a coin . This allowed for the powerful computers and other electronic devices we see today. Read more... 150 px px Signal processing deals with the analysis and manipulation of signals . Signals can be either analog , in which case the signal varies continuously according to the information, or digital , in which case the signal varies according to a series of discrete values representing the information. For analog signals, signal processing may involve the amplification and filtering of audio signals for audio equipment or the modulation and demodulation of signals for telecommunications . For digital signals, signal processing may involve the compression , error checking and error detection of digital signals. Read more...

150 px Telecommunications engineering deals with the transmission of information across a channel such as a coax cable , optical fibre or free space . Transmissions across free space require information to be encoded in a carrier wave in order to shift the information to a carrier frequency suitable for transmission, this is known as modulation . Popular analog modulation techniques include amplitude modulation and frequency modulation . The choice of modulation affects the cost and performance of a system and these two factors must be balanced carefully by the engineer. Once the transmission characteristics of a system are determined, telecommunication engineers design the transmitters and receivers needed for such systems. These two are sometimes combined to form a two-way communication device known as a transceiver . A key consideration in the design of transmitters is their power consumption as this is closely related to their signal strength . If the signal strength of a transmitter is insufficient the signal's information will be corrupted by noise . Read more... Control engineering has a wide range of applications from the flight and propulsion systems of commercial airliners to the cruise control present in many modern automobiles . It also plays an important role in industrial automation . Control engineers often utilize feedback when designing control systems .

For example, in an automobile with cruise control the vehicle's speed is continuously monitored and fed back to the system which adjusts the motor's speed accordingly. Where there is regular feedback, control theory can be used to determine how the system responds to such feedback. Read more... Instrumentation engineering deals with the design of devices to measure physical quantities such as pressure , flow and temperature . These devices are known as instrumentation . The design of such instrumentation requires a good understanding of physics that often extends beyond electromagnetic theory . For example, radar guns use the Doppler effect to measure the speed of oncoming vehicles. Similarly, thermocouples use the Peltier-Seebeck effect to measure the temperature difference between two points. Often instrumentation is not used by itself, but instead as the sensors of larger electrical systems. For example, a thermocouple might be used to help ensure a furnace's temperature remains constant. For this reason, instrumentation engineering is often viewed as the counterpart of control engineering. Read more... 150 px Computer engineering deals with the design of computers and computer systems . This may involve the design of new hardware , the design of PDAs or the use of computers to control an industrial plant . Computer engineers may also work on a system's software .

However, the design of complex software systems is often the domain of software engineering , which is usually considered a separate discipline. Desktop computers represent a tiny fraction of the devices a computer engineer might work on, as computer-like architectures are now found in a range of devices including video game consoles and DVD players . Read more... Project engineering Edit For most engineers not involved at the cutting edge of system design and development, technical work accounts for only a fraction of the work they do. A lot of time is also spent on tasks such as discussing proposals with clients, preparing budgets and determining project schedules. Many senior engineers manage a team of technicians or other engineers and for this reason project management skills are important. Most engineering projects involve some form of documentation and strong written communication skills are therefore very important. The workplaces of electronics engineers are just as varied as the types of work they do. Electronics engineers may be found in the pristine laboratory environment of a fabrication plant, the offices of a consulting firm or in a research laboratory. During their working life, electronics engineers may find themselves supervising a wide range of individuals including scientists, electricians, computer programmers and other engineers. Obsolescence of technical skills is a serious concern for electronics engineers.

Membership and participation in technical societies, regular reviews of periodicals in the field and a habit of continued learning are therefore essential to maintaining proficiency. . 1.Ryder, John and Fink, Donald; (1984). Engineers and Electrons, IEEE Press. ISBN 087942172X . 2.Why Should You Get Licensed?. National Society of Professional Engineers. URL accessed on 11 July 2005. 3.Engineers Act. Quebec Statutes and Regulations (CanLII). URL accessed on 24 July 2005. 4.Shuman, Ellis: “Joy turns to tragedy in collapse of Versailles wedding hall”, Israel Insider, May 27, 2001. 5.Codes of Ethics and Conduct. Online Ethics Center. URL accessed on 24 July 2005. 6.About the IEEE. IEEE. URL accessed on 11 July 2005. 7.About the IEE. The IEE. URL accessed on 11 July 2005. 8.Journal and Magazines. The IEE. URL accessed on 11 July 2005.

9.Electrical and Electronics Engineers, except Computer. Occupational Outlook Handbook. URL accessed on 16 July 2005. (see here regarding copyright) 10.Trevelyan, James; (2005). What Do Engineers Really Do?. University of Western Australia. (seminar with slides) 11.Electrical and Electronics Engineers, except Computer. Occupational Outlook Handbook. URL accessed on 16 July 2005. 12.Electrical and Electronics Engineers, except Computer. Occupational Outlook Handbook. URL accessed on 27 August 2005. and Computer Hardware Engineers. Occupational Outlook Handbook. URL accessed on 27 August 2005. 13.Electrical and Electronics Engineers. Australian Careers. URL accessed on 27 August 2005. 14.Electrical and Electronics Engineers (NOC 2133). Job Futures (National Edition). URL accessed on 27 August 2005. 15.National Science Foundation (2002), Science and Engineering Indicators 2002, Appendix 2-18. 16.Electrical and Electronics Engineers, except Computer.

Occupational Outlook Handbook. URL accessed on 16 July 2005. 17.Electrical engineering degrees awarded, by degree level and sex of recipient: 1966–2001. Science and Engineering Degrees: 1966-2001. URL accessed on 27 August 2005. 18.Department of Education, Science and Training (2004), Australian Australian Science and Technology at a glance 2004 - Human Resources in Science and Technology, slide 10. 19.MEMS the world!. IntelliSense Software Corporation. URL accessed on 17 July 2005. 20.IEEE-USA, IEEE-USA Seeks to Substantiate Information in the H-1B Guest Worker Visa Policy Debate, January 30, 2003. 21.Forbes, Nushad (2003). "Higher Education, Scientific Research and Industrial Competitiveness: Reflections on Priorities for India." First Draft. 22.Engineering degrees awarded, by degree level and sex of recipient: 1966–2001.

Science and Engineering Degrees: 1966-2001. URL accessed on 27 August 2005. 23.Atlas, Terry: “Bangalore's Big Dreams”, U.S. News, February 5, 2005. See also CRC Press Online - News: Engineering Environmental Sensible and Reliable “Green” Electronics Engineering Environmental Sensible and Reliable “Green” Electronics Nov 16, 2014 | Many scientists and engineers consider the birth of electronics to be November 16, 1904, when U.K. engineer Sir John Ambrose Fleming applied for a British patent for his invention: the thermionic diode. In 1880, Thomas Edison discovered that electrons boiling off of a heated filament and filed a patent on the effect, which is called the "Edison effect." In 1904, based on the Edison effect, Sir John Ambrose Fleming invented the two-electrode radio rectifier; or vacuum diode. The valve demonstrated its reliability by successfully detecting radio waves. While Fleming called his device an oscillation valve, it has also been referred to as a thermionic valve, vacuum diode, and a Fleming valve.

On Christmas Eve 1906, engineering professor Reginald Fessenden transmitted a voice and music program in Massachusetts that is picked up as far away as Virginia. In 1907, transcontinental telephone service became possible with Lee De Forest's patent of the triode, or three-element vacuum tube, which electronically amplifies signals. Today, while turning 110 year old, electronics industry remains a young industry facing the challenge of creating environmental sensible and reliable “green” electronics . See More

Question: Which electrical engineer invented the triode valve in 1907?
Answer: Lee De Forest